Evaluation of multipactor thresholds for coaxial lines subject to surface conditioning for the WEST ion cyclotron antenna

Eva Al Hajj Sleiman (1, 2) , Julien Hillairet (1) , Mohamed Belhaj (2) , Sarah Dadouch (2)

1 IRFM - Institut de Recherche sur la Fusion par confinement Magnétique
2 ONERA / DPHY, Université de Toulouse [Toulouse]

Multipactor voltage threshold charts and scaling laws for 30 Ω circular coaxial geometries, relevant to the WEST Ion Cyclotron Resonance Heating antennas, are reproduced using a developed multipactor decision-making algorithm relying on Spark-3D electron time-evolution data. The developed methodology is validated by comparing the simulated multipactor powers to the measured multipactor power thresholds, for a 50 Ω coaxial geometry. The effects of the conditioning, for a WEST antenna-relevant surface sample, on the total electron emission yield and surface properties are studied. The consequences of the conditioning phase on the multipactor voltage thresholds for coaxial transmission lines of 30 Ω and 50 Ω characteristic impedance are also highlighted. It is shown that preliminary baking and conditioning suppress or reduce the range in which multipactor can be triggered.

Keywords: Multipactor; Coaxial cables; TEEY; Conditioning

Keywords: CABLE COAXIAL; MULTIPACTOR; CONDITIONNEMENT

Domains: Engineering Sciences [physics]; Physics [physics]

Eva Al Hajj Sleiman, Julien Hillairet, Mohamed Belhaj, Sarah Dadouch. Evaluation of multipactor thresholds for coaxial lines subject to surface conditioning for the WEST ion cyclotron antenna. Fusion Engineering and Design, 2022, 185, pp.113325. ⟨10.1016/j.fusengdes.2022.113325⟩. ⟨cea-03906700⟩